I purchased my car about a year ago after doing a lot of research on V12 XJs. One of the issues raised frequently in numerous forum discussions as well as mentioned elsewhere(Living with a classic and Harry’s garage) as something to watch was overheating. My car was stored for several years before I purchased it and I knew right away that one of the projects I would take on first was the overhaul of the cooling system.
I first removed all of the hoses, which I think were all original. I cleaned the radiator by leaving white vinegar overnight and then flushing it. I did that a few times until there was no sediment or rusty water coming out. I installed new thermostats, new silicone hoses and filled it with fresh coolant. The next issue was addressing the rusty shroud and cracked wires on the auxilliary fan. The fan itself was working but it certainly saw better days. I had the option of repairing the wiring, finding a good used original fan(original fan is NLA) or buying a replacement aftermarket fan.
I opted for the last option and purchased the fan from Moss Motors for about 300 Euros. OUCH !!!
This still left me with rusty right section of the shroud, on the viscous fan side. I now started looking into options to address this and was going to purchase a good used shroud but realized that, for the same money, I could mount an electric fan. Since I am also doing a Mobeck EFI conversion, where ECU
has capability of controlling an electric fan, it seemed a good way to go.
I actually repaired and painted the original shroud but it still looked off next to the new auxiliary set up.
The best fan I managed to find at the junk yard was a 16" from a Volvo. I heard a lot of good things about Volvo fans from other forums. I also grabbed the relay set up. I will have to figure out how to wire it or I will use a generic 30A relay(bottom right) I purchased for another project.
Other than wiring, the most challenging part will be fabricating a suitable shroud. I went to a local hardware store(Toom) close to my house and bought 2mm thick sheet of aluminium. Last week I ordered a cheap metal brake on Ebay, which showed up today. I mounted it to the work bench with 4 bolts and will start bending tomorrow. Instructions say it will bend up to 1.5mm thick material. I am hoping that it will still work on 2mm as aluminium is much softer than steel.
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Nice progress I think that you should be able to attach more than one photo to a post now.
Hi Ivan,
Nice progress indeed!
I would remove the spacers and fit shorter bolts though.
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I assume there is a thermoswitch on radiator - test it, William…
Good work!
Frank
xj6 85 Sov Europe (UK/NZ)
It’s a V12, so it’s at the water pump inlet.
Looks like a nice car. Thanks for sharing your project with us.
I agree with Aristides that those water pump bolts would look better if they matched the others on the water pump. However, the two on the left of the photo are actually studs and would have to be either cut or removed and shorter bolts put in their place.
One of the frustrations, and there are many, of owning and working on a Jaguar/Daimler where I live is the lack of Imperial size hardware. Finding the right thread bolts and in the right length is a challenge. Of course, they can be ordered if you know the specs, but they usually have to be shipped from abroad, which costs money and time. I might come back later and “clean up” some of these improvisations, but at this point I need to move on with both EFI and fan projects and get the car on the road. I think that as long as the solution is safe, it should at least buy me time to take care of the big stuff and test the car. The other reason for not addressing it now is the ability to go back to viscous fan if the electric fan cannot keep the engine cool enough or if the draw on the alternator is too high with two fans running.
As far as the thermoswitch is concerned, the one on the WP will control the auxiliary fan. Mobeck ECU, which has a water temperature sensor, will control the 16" Volvo fan. It comes with two wires ready to connect to a universal relay. I will therefore not be able to use the original Volvo relay as it is triggered by grounding.
Depends what you’re trying to achieve and what your definition of “cool enough” is.
The original system gets the job done if everything is in good order.
Starting circa 1988 a Bosch alternator was used; about 85 amps output as I recall. It might keep up with the demand. Earlier cars had a Lucas alternator, about 65 amps, that was barely enough output to satisfy demand without any add-ons.
Cheers
DD
water pump bolts on my replacement V12 where awful, I got a complete set from SG Barrett’s, then had them zinc plated, not sure if it will make a difference, but I sept soundly that night.
Before deciding on doing the electric fan conversion I read a lot about similar projects, and not just on Jaguars. Alternator draw seemed to be a very frequent concern. Once I turn the lights, stereo and A/C on and both fans kick in, I am afraid that 85 amps will not cut it. I might have to upgrade the alternator. I am sure there are upgrades available, either from Bosch or someone else.
Today was not a very productive day. I managed a couple of bends. It was harder than I thought but it did come out OK. I think 2mm is the limit for this metal brake.
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It will be marginal at best, most probably it will not.
I would be a bit wary of ‘remanufactured’, Aristides - there are some iffy operators out there…?
Honestly, I think that his original 85A alternator, if in good order, is perfectly adequate. The electric fan adds little, and only runs occasionally with a reasonable good cooling system.
Of course, if he as added a 500+W stereo and likes his music loud and permanent…
Frank
xj6 85 Sov Europe (UK/NZ)
Today was a good day. Working on a car outside is very challenging in Germany. This spring was even worse than usual, but I managed to accomplish a lot on both EFI and fan projects. The shroud is virtually finished. Next will be making brackets and fitting on the radiator.
Thank you, Aristides, for the post you pointed out. I will first try to see how my alternator copes with added load and if not, I might follow your lead .
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Two halves together. I did not paint the inside of the shroud as nobody is going to see that side of it anyway as well as because I ran out of paint.
Fans mounted and now on to brackets, wiring and adjustments. I am almost done with the EFI install as well so I might be able to test both together.
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